The jokes get tired and the characters aren't strong enough to stand up as something you want to see regularly, probably because thety're meant to be funny as one-dimensional people but that doesn't allow for repetition.

I did say that ive slacked off on season 3, but maybe thats because when I found the show I did a s1/s2 marathon in a short span of time so season 3 wasnt the first thing on my list when it started coming out.
Will watch tonight, I have NOTHING to watch nowadays when I am inbetween episodes.